Frequency independent information transmission system

ABSTRACT

The system is used for transmitting information wherein each possible message unit in a set, (e.g. the alpha-numeric symbol set) is defined by a specific interval (I=f s  /f R ) and messages are transmitted by conversion to the interval code and for the sending of signals of any two frequencies (f s  and f R ) that are related by the specific intervals. The signals are received by a receiver which computes the interval, matches it with the pre-defined message unit interval and outputs that message unit. A sequence of message units may be sent using a reference frequency signal and a succession of specific signals each related to the reference frequency by the specific interval for that message unit. A computer program can be utilized for automatically encoding or decoding. The system has the advantages that it is relatively free of errors caused by long term frequency shifting, allows transmission at any frequency level, and allows interacting communication between stations wherein the transmitters operate in entirely different frequency domains. In particular, the system is operable to transmit information in the form of interval-coded tones suitable for interpretation by a human listener. Examples of the use of the system include a clock and voltmeter comprising tone output circuitry.

This is a continuation of application Ser. No. 853,480, filed Apr. 18,1986, now U.S. Pat. No. 4,809,299.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the transmission of information and isespecially concerned with a code transmission system.

2. Description of the Prior Art

Numerous systems for the transmission of information have been proposedSee, for example, U.S. Pat. Nos. 3,366,737 issued to Brown, Jr. for"MESSAGE SWITCHING CENTER FOR ASYNCHRONOUS START-STOP TELEGRAPHCHANNELS", 3,627,951 issued to Batin for "ASYNCHRONOUS COMMUNICATIONSSYSTEM CONTROLLED BY DATA PROCESSING DEVICE", 3,633,172 issued toEggimann et al for "MEANS FOR AND METHOD OF ADDRESS-CODED SIGNALING",3,796,835 issued to Closs et al for "SWITCHING SYSTEM FOR TDM DATA WHICHINDUCES AN ASYNCHRONOUS SUBMULTIPLEX CHANNEL", 3,988,545 issued toKuemmerle et al. for "METHOD OF TRANSMITTING INFORMATION ANDMULTIPLEXING DEVICE FOR EXECUTING THE METHOD", 4,154,983 issued toPedersen for "LOOP CARRIER SYSTEM FOR TELECOMMUNICATION AND DATASERVICES", and 4,390,985 issued to Fourcade et al. for "DEVICE FOR THESYNCHRONIZATION OF DIGITAL DATA TRANSMITTED IN PACKETS".

SUMMARY OF THE INVENTION

The present invention is directed to a system for transmittinginformation wherein the information consists of series of specificmessage units out of a set of possible units, (e.g. a word message madeout of the 26 letters of the alphabet) and includes the step of definingan interval for each of the members of the set. Then the message isconverted into a signal of a reference frequency signal and a series ofinformation signals each having a frequency related to the referencesignal's frequency by the interval so defined. Next this message istransmitted. This set of signals can then be translated back to themessage by a receiver that compares the received signals to determinetheir intervals and compares the intervals so derived to the definedinterval.

The system may be readily adapted to be machine implemented using adigital computer and encompasses a transmitter and a receiver forcarrying out the process.

Since an interval is used, the message can be sent and recognizeddespite shifts in frequency from one message to another or despiteuniform shifts in frequencies. The system has the following advantages:

The Message-Interval Coding in the system is frequency independent and,hence, portable across the frequency spectrum.

The Message-Interval Coding of the system forms a smart system because amessage, identified by a particular interval, can be conveyed at higheror lower frequencies.

The system affords great freedom in hardware design.

The system permits different machines to talk at higher or lowerfrequencies while conveying the same Interval-Coded Message.

The system makes high-frequency machines compatible with low-frequencymachines.

With the Message-Interval Coding of the system, a wide-band machinelistener is capable of understanding both high-frequency andlow-frequency transmitters which convey the same Interval-Coded Message.

The system provides a smart machine transmitter because the transmittercan convey a particular Interval-Coded Message at higher or lowerfrequencies.

Furthermore, the transmitter of the system can be employed in anothermanner to transmit information in the form of Interval-Coded audibletones for direct interpretation by a human listener. When used in thismanner, the machine receiver of the system may be omitted. Examples,including a clock and a voltmeter comprising such tone transmitter, arealso disclosed.

The system, together with the advantages thereof, may best be understoodby reference to the following description taken in connection with theaccompanying drawings, in the several figures of which, like referencenumerals identify like elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a-1c are a set of waveforms useful in explaining the system ofthe present invention.

FIG. 2 is another waveform illustrating one aspect of the system of thepresent invention.

FIG. 3 is yet another waveform for illustrating another aspect of thesystem of the present invention

FIG. 4 is a table for use with the system of the present invention.

FIG. 5 is a flow chart useful in illustrating the overall operation ofthe system.

FIG. 6 is a block diagram of a system for producing or transmittingsignals constructed in accordance with the system of the presentinvention.

FIG. 7 is a more detailed flow chart useful for illustrating theoperation of the system shown in FIG. 6

FIG. 8 is a waveform diagram illustrating a feature of the system of thepresent invention.

FIG. 9 is a block diagram of a receiver system constructed in accordancewith the principles of the present invention.

FIG. 10 is a flow chart illustrating the operation of the system shownin FIG. 9.

FIG. 11 is a circuit and block diagram of one particular embodiment forpart of the system shown in FIG. 9.

FIGS. 12a-12c are a set of waveforms useful in illustrating theoperation of the system of the invention.

FIGS. 13a-13b are schematic block diagrams of a record unit and aplayback unit of the system employing a recording media (such as amagnetic tape).

FIG. 14 is a detailed electrical circuit diagram of the record/playbackunits shown in FIGS. 13a-13b.

FIG. 15 is a block diagram of a clock employing a transmitter systemconstructed in accordance with the principles of the present invention.

FIG. 16 is a block diagram of a measuring device employing a transmittersystem constructed in accordance with the principles of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings and especially to FIGS. 1a-1c, the processesof the present invention may be appreciated from the followingdescription with reference to FIGS. 1a-1c.

It should be noted that while square waves are depicted in the drawings,the principles explained apply to any shaped periodic waveform.

The system or process of the present invention uses the Interval I,between two frequencies of a waveform such as waveforms W_(R) andW_(S)(1) of FIGS. 1a and 1b to identify specific messages or items ofinformation (e.g. the letter "A") from a table of such messages Thesefrequencies may be designated f_(R) for a reference frequency and f_(S)for a signal frequency. Then the Interval I may be defined by thefollowing equation: ##EQU1##

Using the usual definition of the periodic T of a wave as the inverse ofits frequency (T=1/f) this becomes: ##EQU2## where D_(R) and D_(S)represent the duration of a half cycle of the waveform W_(R) or W_(S).

Each interval in a table of intervals can be assigned a differentspecific message. With reference to FIG. 1a and 1b , then, the twowaveforms W_(R) and W_(S)(1) would define an interval: ##EQU3##

Taking the general case, any waveform W_(S)(N) would define an interval:##EQU4## and by defining a message unit, Nth Message, the two waveformsW_(R) and W_(S)(N) yield this Nth Message unit M.sub.(N). If the valueof I_(S)(N) equals I_(k) in the table, which has been assigned aspecific message member M_(k), then M.sub.(N) equals M_(k).

FIG. 4 is one such generalized table As a concrete example, let usassume we wish to transmit a message using the English alphabet We couldthen make up a table such as this:

                  TABLE I                                                         ______________________________________                                                         INTERVAL                                                     MESSAGE UNITS    2  (M/24)                                                    ______________________________________                                        A                1.000000                                                     B                1.029302                                                     C                1.059463                                                     D                1.090507                                                     E                1.122462                                                     F                1.155352                                                     G                1.189207                                                     H                1.224053                                                     I                1.259921                                                     J                1.296839                                                     K                1.334839                                                     L                1.373953                                                     M                1.414213                                                     N                1.455653                                                     O                1.498307                                                     P                1.542210                                                     Q                1.587401                                                     R                1.633915                                                     S                1.681792                                                     T                1.731073                                                     U                1.781797                                                     V                1.834008                                                     W                1.887748                                                     X                1.943063                                                     Y                2.000000                                                     Z                2.058604                                                     Space            2.118926                                                     etc.                                                                          ______________________________________                                    

Thus, a message unit for "Y" could be translated from two waveformsW_(R) and W_(S) wherein the frequency of W_(R) was 10 KHz and that ofW_(S) 20 KHz. Note that it could also be 1 KHz and 2 KHz or 1.13 MHz and2.26 MHz.

(Of course, in a practical receiver of this system any interval within arange about the above precise values would be accepted as being thatinterval.)

The waveforms W_(R) and W_(S)(1), etc. can be transmitted sequentiallyas shown in FIG. 2 and even single cycles of the waveforms used as thereshown. However, in most practical systems it is preferred that thewaveforms W_(R), W_(S)(1), etc. persist for a number of cycles so as tomake the detection of them accomplished easily and with less preciseequivalence. However, this is not necessary for even as short a durationas one half cycle D_(R), D_(S)(1), D_(S)(N) can be used as illustratedin FIG. 3 Again, in this case each message unit is represented by theinterval defined by the equation there set out.

Transmitter

FIG. 5 shows the steps in practicing the process of the presentinvention in the conventional computer flow chart manner. From a startat 12, the first step 14 is to establish the message interval (MI) Table(step 14). The next step 16 is to input specific message units M(1) . .. M(N) (for example the letters and spaces NOW IS THE TIME . . . AID . .. using Table I above ) at step 16 and select the correspondingintervals from the MI Table of stop 14. The final step 18 is to generatethe waves W_(R), W_(S)(1), etc. in accordance with the input of step 16and when this is done the operation is over at step 20

A transmitter 21 for carrying out the process of FIG. 5 is shown in FIG.6 wherein a microcomputer 22 receives the message units (e.g. through akeyboard) at input 24 and selects the proper intervals from a MI Tableunit 26. (This table may take the form of a ROM chip or any othersuitable source). The microcomputer 22 derives a succession of signalsfor a reference waveform and message waveforms and supplies them to anoutput 28. These can be, for example, the duration of half-cycles of thewaveforms D_(R), D_(S)(1). The output 28 feeds a programmable wavegenerator 30 which produces the output wave W_(R), W_(S)(1), etc. on itsoutput 32 This latter output 32 may be fed to a suitable transmissionvehicle such as a transmission line or optic fiber or broadcast antenna

This transmitter has been constructed and successfully operated using aBBC Microcomputer Model B This Microcomputer contains a 6502 CPU and two6522 Versatile Interface Adaptors, where one of which, the USER VIA, isalready connected to the Model B's USER PORT for user applications Amore detailed flow chart for this particular and currently preferredmethod of carrying out the invention is shown in FIG. 7.

In this particular case, the microcomputer 22 may serve as not only themicrocomputer 22, but by placing the Table MI in its RAM as the table26, the USER VIA section can be operated as the generator 30 wherein theoutput waves are obtained across the standard circuit points identifiedas PB7 and OV at the USER PORT of this commercially available computer

The flow chart of FIG. 7 includes a start command 34 which establishes aMI Table at step 36 and accepts input messages at step 38. In responseto the first of these steps, it fetches a pre-selected reference D(half-cycle) at step 40 and in the next stage 42, inverts the logicstate at the output and starts a countdown on D Before the conclusion ofthis countdown it fetches the next signal D (i.e., D_(S)(1), etc.) infunction block 44. If this is not the last D fetched (test block 46) thesystem responds as indicated in block 47 to restart the process ofselecting the next D. If the answer to test 46 is "yes", the systemresponds as indicated by logic block 50 to proceed to countdown on thelast D and as indicated by block 52 to invert logic at the output andproceed to end at 54.

The program for carrying out this operation is as follows:

    __________________________________________________________________________    Transmitter Program I                                                         __________________________________________________________________________     10 REM INVENTED BY HO KIT-FUN                                                 15 REM UNPUBLISHED COPYRIGHT                                                  20 REM                                                                        40 REM NORTH POINT                                                            50 REM HONG KONG                                                              60 REM                                                                        80 REM PRESTOB18G                                                             85 REM                                                                        90 ?&FE6B=&CO : REM SET USER 6522 AT FREE-RUNNING MODE                        92 ?&FE62=&80 : REM INITIALIZE OUTPUT (SET PB7 AT HIGH)                       94 ?&FE6E=&00 : REM INTERRUPT DISABLED                                       100 REM                                                                       110 REM ESTABLISH MESSAGE-INTERVAL CODING TABLE                               120 DR=3000 : REM SET REFERENCE "HALF-CYCLE" DURATION,                                  PROGRAMMABLE                                                        130 DELAY%=2                                                                  140 DSH%=&0DA0 : DSL%=&0DC0 : REM LOCATION OF MI TABLE                        150 FOR M = 0 TO 31                                                           170 REM FOR EXAMPLE 32-STATE MESSAGES IN THIS                                           DEMONSTRATION                                                       180 REM (EACH MESSAGE HAS THE SAME INFORMATION CONTENT                                  AS 5 BINARY BITS)                                                   200 DS% = INT 2  (-M/24)*DR : REM COMPUTE SIGNAL "HALF-                                 CYCLE" DURATION                                                     210 REM MESSAGES MESSAGES CODED BY                                            220 REM INTERVALS 2  (0/24), 2  (1/24), 2  (2/24), . . . ,                              2  (31/24)                                                          230 DS%=DS%-DELAY% : REM DELAY CORRECTION                                     232 REM TRUE DURATION = PROGRAMMED DURATION + DELAY                           235 DSH%?M=DS% DIV 256                                                        238 DSL%?M=DS% MOD 256                                                        240 NEXT M                                                                    290 REM INPUT MESSAGES                                                        300 N=128 : REM TAKE N INPUT MESSAGE UNITS                                              (N=1,5,16,64 ETC., PROGRAMMABLE)                                    320 DTA%=&3000 : ?DTA%=N                                                      330 FOR NUM% = N TO 1 STEP -1                                                 340 M=GET : REM SPECIFIC MESSAGE UNIT OF A DEPRESSED                                    KEY                                                                 342 IF M=32 THEN M=27 ELSE M=M-65                                             350 DTA%? (NUM%)=M                                                            360 NEXT                                                                      390 REM USING THE USER VIA                                                    400 REM GENERATE WAVES                                                        410 REM IN ACCORDANCE WITH MI TABLE                                           420 FOR PASS = 0 TO 3 STEP 3                                                  430 P%=&0D00                                                                  440 [                                                                         450 OPT PASS                                                                  500 LDA DSL%                                                                  510 STA &FE64                                                                             LOAD 16-BIT COUNTER                                               520 LDA DSH%                                                                              WITH                                                              530 STA &FE65                                                                             REFERENCE DURATION                                                540 LDX DTA%                                                                  550 .LOOP LDA DTA%,X                                                          560 TAY                                                                       570 LDA DSL%,Y                                                                580 STA &FE66                                                                             LOAD 16-BIT LATCH                                                 590 LDA DSH%,Y                                                                            WITH                                                              600 STA &FE67                                                                             SIGNAL DURATION                                                   620 .STS BIT &FE6D                                                            630 BVC STS WAIT TILL A TIME-OUT                                              640 DEX                                                                       650 BEQ STP                                                                   660 JMP LOOP                                                                  690 .STP LDA #&80                                                             700 STA &FE6B                                                                 710 RTS                                                                       720 ]                                                                         730 NEXT PASS                                                                 740 CALL &0D00                                                                770 END                                                                       __________________________________________________________________________

The flow chart of FIG. 7 and this program consist of the procedure usedto realize a machine which conveys a message by producing INTERVAL-CODED"HALF-CYCLE" WAVELETS like those shown in FIG. 3. It follows that bygenerating each of such "HALF-CYCLE" twice one obtains "SINGLE-CYCLE"WAVES like those shown in FIG. 2. And by generating each of such"HALF-CYCLE" several times one obtains WAVE TRAINS like those in FIG. 1.

The output produced by the system of FIGS. 6 and 7 is shown in FIG. 8wherein the output at line 32 is depicted from the reference D_(R) andthe D_(S)(1) and D_(S)(2) with the various logic events depicted intheir timed relationship to the output.

Receiver

Referring to FIG. 9, there is depicted a receiver 60 having an input 62,on which the waveforms WR, WS(1), . . . W_(S) (N) are received from asuitable transmission media such as a transmission line or optic fiberor antenna. This input 62 delivers the waveforms to a wave durationmeasurement circuit 64 which serves to measure the duration D and feedsa succession of duration information on D_(R), D_(S)(1), etc. to amicrocomputer 66. An MI Table 68 which is substantially similar to thatof the transmitter sending the signals W_(R), W_(S)(1), etc. is providedand the computer computes the intervals and derives from the table 68the message unit M(1), . . . M(N). These message units are fed to asuitable output 70 such as a Cathode Ray Tube display or a printer orboth.

The MI Table 26 of the transmitter 21 would be one of precise intervalsbut as stated above the receiver should recognize calculated intervalswithin a range of values about the precise values. This can be done byhaving the program select the closest interval or by having the MI Table68 at the receiver contain a range. The system currently utilizes thislatter approach and has the following MI Table 68 for the receiver 60for the particular message unit given above:

                  TABLE II                                                        ______________________________________                                                      INTERVAL BOUNDARY                                               MESSAGE UNIT  2  (M-0.5)/24)                                                  ______________________________________                                                      0.985663                                                                      1.014545                                                        B                                                                                           1.044273                                                        C                                                                                           1.074873                                                        D                                                                                           1.106369                                                        E                                                                                           1.138788                                                        F                                                                                           1.172157                                                        G                                                                                           1.206504                                                        H                                                                                           1.241857                                                        I                                                                                           1.278247                                                        J                                                                                           1.315702                                                        K                                                                                           1.354255                                                        L                                                                                           1.393938                                                        M                                                                                           1.434783                                                        N                                                                                           1.476826                                                        O                                                                                           1.520100                                                        P                                                                                           1.564642                                                        Q                                                                                           1.610490                                                        R                                                                                           1.657681                                                        S                                                                                           1.706255                                                        T                                                                                           1.756252                                                        U                                                                                           1.807714                                                        V                                                                                           1.860684                                                        W                                                                                           1.915206                                                        X                                                                                           1.971326                                                        Y                                                                                           2.029090                                                        Z                                                                                           2.088547                                                        Space                                                                                       2.149746                                                        etc.                                                                          ______________________________________                                    

That is, in the TRANSMITTER 21, the MI Table 26 is in the form ofmessage-wave duration correspondence, and in the RECEIVER 60, the MITable 68 is in the form of message-interval boundary correspondence.

The MI Table in TABLE I can be an example of 32-state coding, where eachmessage unit has the same information content as 5 binary bits, i.e. 1out of 32. From TABLE I it is apparent that similar MI Tables for coding4-, 8-, 10-, and 24-state messages, etc. may be used.

The receiver computer 66 may also be a BBC Microcomputer Model B whichis programmed in accordance with the flow diagram of FIG. 10 and theprogram given below. In this case the MI Table 68 is again held in theRAM.

The receiver 60 may not be easily made from just the aforementionedcomputer but requires a wave measurement circuit 64. One preferredcircuit 64 is depicted in FIG. 1.

The elements, values and interconnection of the circuit are given inFIG. 11. The circuit of FIG. 11 is connected to the I/O port known asthe 1-MH_(z) Extension Bus of the BBC Microcomputer. The conductorsR/NW, NP, AO, A1, A2, 0, D0, D1, D2, D3, D4, D5, D6, D7, and G of thecircuit of FIG. 11 are respectively connected to R/NW, NPGFC, A0, A1,A2, 1MH_(z), D0, D1, D2, D3, D4, D5, D6, D7 and OV of The 1-MH_(z)Extension Bus.

In overall operation, the circuit 64 serves to measure the time instantat the occurrence of each waveform transition of the input wave andpresent this information to the Microcomputer 66.

At the input R of the circuit 64 the received wave W is fed to invertingbuffer 71 to produce at its output a inverted wave NW which is invertedonce again by inverter 73 to recover an uninverted wave W at the mostsignificant bit D15 of a 16-bit latch 74. By using decoder 76, flip-flop77 and switch 78 the computer 66 selectively feeds the waveform W or NW,alternately, to LE to produce a time-related latching waveform LW, whichmay be illustrated with FIG. 12C. By sensing the HIGH or LOW voltagelevel of and, hence, transition in the waveform W at Dl5 the computer 66(a) initializes LW to HIGH, (b) detects the occurrence of waveformtransition in W, (c) takes a latched counter reading at 74 captured fromcounter 79 by a HIGH-to-LOW TRANSITION in LW, and (d) resets LW to HIGHto unlatch 74 for another capture. Clock pulses φ are provided (e.g.from computer 66) to operate the counter 79 and through inverter 80 tooperate switch 78. The captured counter readings obtained in this mannerprovide information on durations D_(R), D_(S)(1), etc. of the receivedwaveform W.

Referring to FIG. 10 the program upon start 82 initially establishes theMI Table in its RAM at step 84, e.g. by coping it from a disc drive orother more permanent memory. (In the case of a dedicated receiver thiscould take the form of a ROM chip). Thereafter, at block 86, it measuresthe duration (with unit 64) of the received waves and, at block 88,identifies the intervals and message units in accordance with the MITable and when completed terminates the program at end 89.

A suitable program that has been successfully operated in theaforementioned particular computer is as follows:

    __________________________________________________________________________    Receiver Program I                                                            __________________________________________________________________________    5000                                                                              REM INVENTED BY HO KIT-FUN                                                5001                                                                              REM UNPUBLISHED COPYRIGHT                                                 5002                                                                              REM                                                                       5004                                                                              REM P.O. BOX 54504                                                        5006                                                                              REM NORTH POINT                                                           5008                                                                              REM HONG KONG                                                             5010                                                                              REM                                                                       5020                                                                              REM PRESTOL15F                                                            5050                                                                              N=128 : REM NUMBER OF SIGNALS                                             5060                                                                              n=N+1 : REM NUMBER OF WAVES                                               5070                                                                              CONSTANT1%=128*256                                                        5080                                                                              DIM Ibound(32),DSB%(32),CTIME%(n),DURATION%(N),                                     STORAGE%(N),M(N)                                                    5090                                                                              HTIME=&5500                                                               5100                                                                              LTIME-HTIME+n+1                                                           5105                                                                              STORAGE%=&4000 : REM STORAGAE LOCATION                                    5108                                                                              FOR M=0 TO 32:Ibound(M)=2  ((M-0.5)/24):NEXT :                                      REM INTERVAL BOUNDARIES                                             5110                                                                              W=&FC03  :REM WAVEFORM W                                                  5120                                                                              NW=&FC02 :REM WAVEFORM NW                                                 5130                                                                              HBYTE=&FC01 :REM 16-BIT LATCH LOCATION                                    5140                                                                              LBYTE=&FC00 :REM 16-BIT LATCH LOCATION                                    5150                                                                              FOR PASS=0 TO 3 STEP 3                                                    5160                                                                              P%=&D00                                                                   5170                                                                              [                                                                         5180      OPT PASS                                                            5190      LDY#0                                                               5200      LDA HBYTE  READ HIGH BYTE OF 16-BIT LATCH                           5210      BMI WAVE                                                            5220                                                                              .NWAVE                                                                              LDA NW     SWITCH TO NW WAVE                                        5230                                                                              .NWATI                                                                              LDA HBYTE                                                           5240      BPL NWATI                                                           5250      AND #127                                                            5260      STA HTIME,Y                                                         5270      LDA LBYTE                                                           5280      STA LTIME,Y                                                         5300      CPY #n                                                              5310      BEQ STOP1                                                           5315      INY                                                                 5320                                                                              .WAVE LDA W      SWITCH TO W WAVE                                         5330                                                                              .WATI LDA HBYTE                                                           5340      BMI WATI                                                            5350      STA HTIME,Y                                                         5360      LDA LBYTE                                                           5370      STA LTIME,Y                                                         5390      CPY #n                                                              5400      BEQ STOP1                                                           5405      INY                                                                 5410      JMP NWAVE                                                           5420                                                                              .STOP1                                                                              RTS                                                                 5430                                                                              ]                                                                         5440                                                                              NEXT                                                                      5450                                                                              CALL &0D00                                                                5470                                                                              REM COUNTER TIME CAPTURED (i.e. CAPTURED                                            TIME INSTANT )                                                      5480                                                                              FOR Y=0 TO n                                                              5490                                                                              CTIME%(Y) = (?(HTIME+Y))*256+?(LTIME+Y)                                   5500                                                                              NEXT                                                                      5520                                                                              REM DURATION                                                              5530                                                                              FOR Y=0 TO N                                                              5540                                                                              DURATION%(Y) = CTIME%(Y+1) - CTIME%(Y)                                    5550                                                                              IF DURATION%(Y) < 0 THEN DURATION%(Y) =                                             DURATION%(Y) + CONSTANT1%                                           5552                                                                              NEXT                                                                      5555                                                                              REM MESSAGE-INTERVAL TABLE AND MESSAGE                                              IDENTIFICATION                                                      5560                                                                              DSB%(0)= INT DURATION%(0)/Ibound(0)                                       5562                                                                              DSB%(1)= INT DURATION%(0)/Ibound(1)                                       5564                                                                              DSB%(2)= INT DURATION%(0)/Ibound(2)                                       5565                                                                              DSB%(3)= INT DURATION%(0)/Ibound(3)                                       5566                                                                              DSB%(4)= INT DURATION%(0)/Ibound(4)                                       5570                                                                              DSB%(5)= INT DURATION%(0)/Ibound(5)                                       5572                                                                              DSB%(6)= INT DURATION%(0)/Ibound(6)                                       5574                                                                              DSB%(7)= INT DURATION%(0)/Ibound(7)                                       5576                                                                              DSB%(8)= INT DURATION%(0)/Ibound(8)                                       5578                                                                              DSB%(9)= INT DURATION%(0)/Ibound(9)                                       5580                                                                              DSB%(10)=  INT DURATION%(0)/Ibound(10)                                    5582                                                                              DSB%(11)= INT DURATION%(0)/Ibound(11)                                     5584                                                                              DSB%(12)= INT DURATION%(0)/Ibound(12)                                     5586                                                                              DSB%(13)= INT DURATION%(0)/Ibound(13)                                     5588                                                                              DSB%(14)= INT DURATION%(0)/Ibound(14)                                     5590                                                                              DSB%(15)= INT DURATION%(0)/Ibound(15)                                     5592                                                                              DSB%(16)= INT DURATION%(0)/Ibound(16)                                     5593                                                                              DSB%(17)= INT DURATION%(0)/Ibound(17)                                     5594                                                                              DSB%(18)= INT DURATION%(0)/Ibound(18)                                     5595                                                                              DSB%(19)= INT DURATION%(0)/Ibound(19)                                     5596                                                                              DSB%(20)= INT DURATION%(0)/Ibound(20)                                     5597                                                                              DSB%(21)= INT DURATION%(0)/Ibound(21)                                     5598                                                                              DSB%(22)= INT DURATION%(0)/Ibound(22)                                     5599                                                                              DSB%(23)= INT DURATION%(0)/Ibound(23)                                     5600                                                                              DSB%(24)= INT DURATION%(0)/Ibound(24)                                     5601                                                                              DSB%(25)= INT DURATION%(0)/Ibound(25)                                     5602                                                                              DSB%(26)= INT DURATION%(0)/Ibound(26)                                     5603                                                                              DSB%(27)= INT DURATION%(0)/Ibound(27)                                     5604                                                                              DSB%(28)= INT DURATION%(0)/Ibound(28)                                     5605                                                                              DSB%(29)= INT DURATION%(0)/Ibound(29)                                     5606                                                                              DSB%(30)= INT DURATION%(0)/Ibound(30)                                     5607                                                                              DSB%(31)= INT DURATION%(0)/Ibound(31)                                     5608                                                                              DSB%(32)= INT DURATION%(0)/Ibound(32)                                     6000                                                                              FOR Y=1 TO N                                                              6010                                                                              IF DURATION%(Y) > DSB%(0) THEN PRINT "ERROR                                         IN MESSAGE (";Y;")": M(Y)=127:GOTO 8000                             6020                                                                              IF DURATION%(Y) > DSB%(1) THEN M(Y)=0:GO TO 8000                          6030                                                                              IF DURATION%(Y) > DSB%(2) THEN M(Y)=1:GO TO 8000                          6040                                                                              IF DURATION%(Y) > DSB%(3) THEN M(Y)=2:GO TO 8000                          6050                                                                              IF DURATION%(Y) > DSB%(4) THEN M(Y)=3:GO TO 8000                          6060                                                                              IF DURATION%(Y) > DSB%(5) THEN M(Y)=4:GO TO 8000                          6070                                                                              IF DURATION%(Y) >  DSB%(6) THEN M(Y)=5:GO TO 8000                         6080                                                                              IF DURATION%(Y) > DSB%(7) THEN M(Y)=6:GO TO 8000                          6090                                                                              IF DURATION%(Y) > DSB%(8) THEN M(Y)=7:GO TO 8000                          6100                                                                              IF DURATION%(Y) > DSB%(9) THEN M(Y)=8:GO TO 8000                          6110                                                                              IF DURATION%(Y) > DSB%(10) THEN M(Y)=9:GO TO 8000                         6120                                                                              IF DURATION%(Y) > DSB%(11) THEN M(Y)=10:GO TO 8000                        6130                                                                              IF DURATION%(Y) > DSB%(12) THEN M(Y)=11:GO TO 8000                        6140                                                                              IF DURATION%(Y) > DSB%(13) THEN M(Y)=12:GO TO 8000                        6150                                                                              IF DURATION%(Y) > DSB%(14) THEN M(Y)=13:GO TO 8000                        6160                                                                              IF DURATION%(Y) > DSB%(15) THEN M(Y)=14:GO TO 8000                        6170                                                                              IF DURATION%(Y) > DSB%(16) THEN M(Y)=15:GO TO 8000                        6171                                                                              IF DURATION%(Y) > DSB%(17) THEN M(Y)=16:GO TO 8000                        6172                                                                              IF DURATION%(Y) > DSB%(18) THEN M(Y)=17:GO TO 8000                        6173                                                                              IF DURATION%(Y) > DSB%(19) THEN M(Y)=18:GO TO 8000                        6174                                                                              IF DURATION%(Y) > DSB%(20) THEN M(Y)=19:GO TO 8000                        6175                                                                              IF DURATION%(Y) > DSB%(21) THEN M(Y)=20:GO TO 8000                        6176                                                                              IF DURATION%(Y) > DSB%(22) THEN M(Y)=21:GO TO 8000                        6177                                                                              IF DURATION%(Y) > DSB%(23) THEN M(Y)=22:GO TO 8000                        6178                                                                              IF DURATION%(Y) > DSB%(24) THEN M(Y)=23:GO TO 8000                        6179                                                                              IF DURATION%(Y) > DSB%(25) THEN M(Y)=24:GO TO 8000                        6180                                                                              IF DURATION%(Y) > DSB%(26) THEN M(Y)=25:GO TO 8000                        6181                                                                              IF DURATION%(Y) > DSB%(27) THEN M(Y)=26:GO TO 8000                        6182                                                                              IF DURATION%(Y) > DSB%(28) THEN M(Y)=27:GO TO 8000                        6183                                                                              IF DURATION%(Y) > DSB%(29) THEN M(Y)=28:GO TO 8000                        6184                                                                              IF DURATION%(Y) > DSB%(30) THEN M(Y)=29:GO TO 8000                        6185                                                                              IF DURATION%(Y) > DSB%(31) THEN M(Y)=30:GO TO 8000                        6186                                                                              IF DURATION%(Y) > DSB%(32) THEN M(Y)=31:GO TO 8000                        7000                                                                              PRINT "ERROR IN MESSAGE (";Y;")":M(Y)=255:GOTO 8000                       8000                                                                              STORAGE%?Y = M(Y)                                                         8115                                                                              IF STORAGE%?Y=27 THEN PRINT CHR$(32); ELSE PRINT CHR                                (65+STORAGE%?Y);                                                    8200                                                                              NEXT                                                                      8300                                                                              END                                                                       __________________________________________________________________________

The computer is programmed with the above program to measure the wavedurations by recording the time instants as each transition of the waveoccurs. The procedure for measuring the wave durations id depicted inthe timing diagram shown in FIG. 12a-12c.

The RECEIVER 60 thus automatically interprets the interval-coded waves,identifies and outputs the message conveyed, and stores the messages forpossible subsequent use.

Message Storage/Retrieval System

Referring to FIGS. 13a and 13b there is depicted therein a novel MessageStorage/Retrieval system 90 which may operate at equal or differingspeeds during storage and subsequent retrieval, i.e. one novel featureof the invented System is that its principle of operation is independentof the operating speeds.

The System 90 is realized by inserting between the Transmitter 21 andthe Receiver 60, a wave-transition record/playback unit such as amagnetic or optical recorder 91. No modification is required on theTransmitter and Receiver in spite of the fact that with differing recordand playback speeds the waves first recorded and the waves subsequentlyretrieved are in different time scales. Such operation is possiblebecause the messages are interval coded and hence, NOT frequencyspecific.

A possible wave-transition record/playback unit for use in the system 90can be realized with a commercially available tape deck and additionalhardware as shown in FIG. 14. For example, a TEAC (trade mark) A-4300with open-reel tape Maxell (trade mark) XLI 35-90B is used with itsrecording level adjusted such that its monitor line output is about 0.6volts peak-to-peak. Its playback level is adjusted to give a signal ofabout 2 volts peak-to-peak at circuit point Y.

The Interval-coded waves from the Transmitter 21 are fed to the inputLINE IN of the tape deck 91 and recorded at speed 1 (e.g. at 7.5 ips).Upon playback at speed 2 (which may be different to speed 1, e.g. at3.25 ips) the interval-coded wave first recorded is retrieved and outputat LINE OUT of the tape deck operating at playback mode 92. The signalis fed to a buffer, through a capacitor 94 and resistor 96 to theinverting input of an operational amplifier 98 which has a non-invertinginput biased to +6 V, i.e. 1/2 Vcc A portion of the output ofoperational amplifier 98 is fed through a resistor 100 to chassis groundand through resistor 102 back to its inverting input. The other portionof the output is fed to a differentiator, through a resistor 104 andcapacitor 106 to the inverting input of an operational amplifier 108which has a non-inverting input biased to +6 V and a portion of itsoutput is fed through resistor 110 to chassis ground and throughresistor 112 back to its inverting input The other portion of the outputof the operational amplifier 108 is fed through circuit point Y andcapacitor 114 to a Schmitt trigger 116. The Schmitt trigger 116 consistsof a MC1455 TIMER with its R and V+points connected to +5 V, its GND tochassis ground, and its input points TH and TR tied together at themid-point of a potential divider formed with equal resistors 118 and 20across +5 V and chassis ground The interval-coded output waves from theSchmitt trigger 116 are fed to the Receiver 60.

The system of the present invention is quite versatile and may beemployed in different manners One such manner would be to use a set ofinterval-coded durations differing by equal duration increments. (Forexample using a set of interval-coded durations such as . . . 2494,2497, 2500, 2503, . . . etc. wherein the duration increment is 3 aspractised in a following concrete example.) In this manner of MI codingit should be noted that if the least duration in the set ispredetermined and the magnitude of the equal duration increment alsopredetermined then there is a preferred number of interval-codeddurations for the set, i.e. a preferred coding for speedy transmissionsof random information as indicated in TABLE III.

                  TABLE III                                                       ______________________________________                                                               PREFERRED                                                                     NUMBER                                                  ##STR1##              OF STATES FOR CODING                                   ______________________________________                                        0.2                    8                                                      0.07                   16                                                     0.025                  32                                                     0.0098                 64                                                     0.00404                128                                                    0.00172                256                                                    0.15                   10                                                      etc.                  etc.                                                   ______________________________________                                    

TABLE III shows specifically the preferred MI coding, respectively, foreach of several cases where the ratio of (equal durationincrement)/(least duration of the set) is predetermined. And thepreferred number of interval-coded durations for each case is found tobe 8, 16, 32, 64, 128, 256 and 10, respectively. The use of TABLE III isfurther explained with the following example: Say, if the least durationand magnitude of duration increment for such coding are chosen to be 100and 20, respectively, then, from TABLE III, 8-state (1-of-8 message)coding is the preferred coding and in this case the set ofinterval-coded durations should be 100, 120, 140, 160, 180, 200, 220,and 240.

As a concrete example of this system, using 256-interval coding, it canbe achieved by coupling the specific transmitter 21 to the specificreceiver 60 described above through a suitable transmission media, withthe transmitter 21 programmed with the program hereafter listed:

    __________________________________________________________________________    Transmitter Program II                                                        __________________________________________________________________________     10 REM INVENTED BY HO KIT-FUN                                                 15 REM UNPUBLISHED COPYRIGHT                                                  20 REM                                                                        30 REM P.O. Box 54504                                                         40 REM NORTH POINT                                                            50 REM HONG KONG                                                              60 REM                                                                        80 REM PRESTOB25A                                                             85 REM                                                                        90 ?&FE6B=&CO : REM SET USER 6522 AT FREE-RUNNING MODE                        92 ?&FE62=&80 : REM INITIALIZE OUTPUT (SET PB7 AT HIGH)                       94 ?&FE6E=&00 : REM INTERRUPT DISABLED                                       100 REM                                                                       110 REM ESTABLISH MESSAGE-INTERVAL CODING TABLE                               120 DR%=2509 : REM SET REFERENCE "HALF-CYCLE"                                           DURATION, PROGRAMMABLE                                              125 DD%=3 : REM DURATION INCREMENT                                            130 DELAY%=2                                                                  140 DSL%=&4000: "DSH%=&5000 : REM LOCATION OF MI TABLE                        145 DIM LOCATION%(255)                                                        150 FOR M = 0 TO 255 : REM THE MESSAGE IS ANY INTEGER                                   IN THE RANGE 0-255                                                  180 REM (EACH MESSAGE HAS THE SAME INFORMATION CONTENT                                  AS 8 BINARY BITS)                                                   200 DS%=DR%-M*DD% : REM COMPUTE SIGNAL "HALF-CYCLE"                                     DURATION                                                            230 DS%=DS%-DELAY% : REM DELAY CORRECTION                                     232 REM TRUE DURATION = PROGRAMMED DURATION + DELAY                           235 DSH%?M=DS% DIV 256                                                        238 DSL%?M=DS% MOD 256                                                        240 NEXT M                                                                    245 REM: FOR A SPECIFIC RANDOMLY ASSIGNED MI TABLE                            250 DATA  21,36,51,1                                                                              231,198,40,125                                                      2,111,159,10,                                                                           68,220,232,5                                              251 DATA  61,123,222,249                                                                          46,19,92,151,                                                       188,215,3,4,                                                                            56,101,223,175                                            252 DATA  77,8,25,26,                                                                             97,132,255,69,                                                      105,143,211,6,                                                                          90,228,196,203                                            253 DATA  83,49,126,119,                                                                          246,9,43,117,                                                       208,29,30,224,                                                                          138,139,13,17                                             254 DATA  157,182,201,127,                                                                        52,33,147,113,                                                      55,28,115,187,                                                                          194,243,64,22                                             255 DATA  59,226,238,200,                                                                         87,190,41,15,                                                       66,72,229,240,                                                                          253,75,31,23                                              256 DATA  122,18,45,62,                                                                           191,205,24,221,                                                     44,245,109,93,                                                                          42,14,186,227                                             257 DATA  155,154,153,39,                                                                         11,71,76,104,                                                       95,100,169,207,                                                                         216,144,131,120                                           258 DATA  150,140,130,160,                                                                        168,212,233,244,                                                    177,166,48,73,                                                                          96,112,165,172                                            259 DATA  133,170,219,242,                                                                        27,53,78,108,                                                       136,145,146,213,                                                                        236,250,199,50                                            260 DATA  184,185,148,60,                                                                         16,80,82,98,                                                        178,209,210,241,                                                                        152,54,57,114                                             261 DATA  110,70,32,86,                                                                           89,135,197,247,                                                     206,116,65,67,                                                                          74,141,204,239                                            262 DATA  252,156,174,134,                                                                        84,88,158,230,                                                      202,149,161,217,                                                                        91,94,103,118                                             263 DATA  128,99,106,102,                                                                         225,171,163,167,                                                    192,193,189,181,                                                                        179,195,176,0                                             264 DATA  137,237,107,38,                                                                         164,235,183,20,                                                     58,173,218,251,                                                                         35,63,124,162                                             265 DATA  214,79,37,142,                                                                          180,81,12,129,                                                      234,248,254,34,                                                                         47,85,7,121                                               268 LOCATION%=&3800                                                           270 FOR MESSAGE% = 0 TO 255                                                   272 READ M                                                                    275 LOCATION%?(MESSAGE%) = M                                                  280 NEXT                                                                      290 REM INPUT MESSAGES                                                        300 N=128 : REM TAKE N INPUT MESSAGE UNITS                                              (N =1,11,128 ETC., PROGRAMMABLE)                                    320 DTA%=&3000 : ?DTA%=N                                                      330 FOR NUM% = N TO 1 STEP -1                                                 340 INPUT MESSAGE% :REM e.g. CONFIDENTIAL DIGITAL DATA                        350 DTA%?(NUM%)=LOCATION%?(MESSAGE%)                                          360 NEXT                                                                      (Lines 390 to 770 same as in Transmitter Program I above)                     __________________________________________________________________________

The receiver 60 of FIGS. 9 and 11 may be employed with Microcomputer 66,programmed with the following program.

    __________________________________________________________________________    Receiver Program II                                                           __________________________________________________________________________    5000                                                                              REM INVENTED BY HO KIT-FUN                                                5001                                                                              REM UNPUBLISHED COPYRIGHT                                                 5002                                                                              REM                                                                       5004                                                                              REM P.O. BOX 54504                                                        5006                                                                              REM NORTH POINT                                                           5008                                                                              REM HONG KONG                                                             5010                                                                              REM                                                                       5020                                                                              REM PRESTOL23A                                                            5050                                                                              N=128 : REM NUMBER OF SIGNALS                                             5060                                                                              n=N+1 : REM NUMBER OF WAVES                                               5070                                                                              CONSTANT1%=128*256                                                        5080                                                                              DIM Ibound(256),DSB(257),CTIME%(n), DURATION%(N),                                   STORAGE%(N),M(256),LOCATION%(256)                                   5090                                                                              HTIME=&5500                                                               5100                                                                              LTIME=HTIME+n+1                                                           5105                                                                              STORAGE%=&4000 : REM STORAGAE LOCATION                                    5107                                                                              REM INTERVAL BOUNDARIES AS PER TRANSMITTER MI TABLE,                                i.e. "DSB=DR%-(m-0.5)*DD%" AND                                                "Ibound(M)=DR%/DSB"                                                 5108                                                                              FOR m=0 TO 256:Ibound(m)=2509/(2509-(m-0.5)*3):                                     NEXT:REM INTERVAL BOUNDIES                                          (Lines 5110 to 5555 same as Receiver Program I, above)                        5560                                                                              FOR m=0 TO 256:DSB(m)=DURATION%(0)/Ibound(m):NEXT                         5570                                                                              REM FOR A SPECIFIC RANDOMLY ASSIGNED MI TABLE                             5600                                                                              DATA  223, 3, 8, 26,                                                                          27, 15, 43, 254                                                     33, 53, 11, 116                                                                         246, 62, 109, 87                                          5610                                                                              DATA  164, 63, 97, 21,                                                                        231, 0, 79, 95,                                                     102, 34, 35, 148                                                                        73, 57, 58, 94                                            5620                                                                              DATA  178, 69, 251, 236,                                                                      1, 242, 227, 115,                                                   6, 86, 108, 54,                                                                         104, 98, 20, 252                                          5630                                                                              DATA  138, 49, 159, 2,                                                                        68, 149, 173, 72,                                                   28, 174, 232, 80,                                                                       163, 16, 99, 237                                          5640                                                                              DATA  78, 186, 88, 187,                                                                       12, 39, 177, 117,                                                   89, 139, 188, 93,                                                                       118, 32, 150, 241                                         5650                                                                              DATA  165, 245, 166, 48,                                                                      196, 253, 179, 84,                                                  197, 180, 44, 204,                                                                      22, 107, 205, 120                                         5660                                                                              DATA  140, 36, 167, 209,                                                                      121, 29, 211, 206,                                                  119, 40, 210, 226,                                                                      151, 106, 176, 9                                          5670                                                                              DATA  141, 71, 175, 74,                                                                       180, 55, 207, 51,                                                   127, 255, 96, 17,                                                                       238, 7, 50, 67                                            5680                                                                              DATA  208, 247, 130, 126,                                                                     37, 144, 195, 181,                                                  152, 224, 60, 61,                                                                       129, 189, 243, 41                                         5690                                                                              DATA  125, 153, 154, 70,                                                                      162, 201, 128, 23,                                                  172, 114, 113, 112,                                                                     193, 64, 198, 10                                          5700                                                                              DATA  131, 202, 239, 214,                                                                     228, 142, 137, 215,                                                 132, 122, 145, 213                                                                      143, 233, 194, 31                                         5710                                                                              DATA  222, 136, 168, 220,                                                                     244, 219, 65, 230,                                                  160, 161, 110, 75,                                                                      24, 218, 85, 100                                          5720                                                                              DATA  216, 217, 76, 221,                                                                      46, 182, 5, 158,                                                    83, 66, 200, 47,                                                                        190, 101, 184, 123                                        5730                                                                              DATA  56, 169, 170, 42,                                                                       133, 155, 240, 25,                                                  124, 203, 234, 146                                                                      13, 103, 18, 30                                           5740                                                                              DATA  59, 212, 81, 111,                                                                       45, 90, 199, 4,                                                     14, 134, 248, 229                                                                       156, 225, 82, 191                                         5750                                                                              DATA  91, 171, 147, 77,                                                                       135, 105, 52, 183,                                                  249, 19, 157, 235,                                                                      192, 92, 250, 38                                          5800                                                                              LOCATION%=&6000                                                           5820                                                                              FOR M=0 TO 255                                                            5840                                                                              READ MESSAGE%                                                             5860                                                                              LOCATION%?M=MESSAGE%                                                      5880                                                                              NEXT                                                                      6000                                                                              FOR Y=1 TO N                                                              6010                                                                              IF DURATION%(Y) DSB(0) THEN PRINT "ERROR IN                                         MESSAGE (";Y;")": M(Y)=127: GOTO 8000                               6020                                                                              m=1                                                                       6030                                                                              IF DURATION%(Y) > DSB(m) THEN M(Y)=m-1 : GOTO 8000                        6040                                                                              m=m+1                                                                     6045                                                                              IF m=257 THEN PRINT "ERROR IN MESSAGE (";Y'")" :                                    M(Y)=255: GOTO 8000                                                 6050                                                                              GOTO 6030                                                                 8000                                                                              STORAGE%?Y =LOCATION%?M(Y)                                                8100                                                                              PRINT "MESSAGE (";Y;") = ";STORAGE%?Y :REM DISPLAY                                  CONFIDENTIAL DATA                                                   8200                                                                              NEXT                                                                      8300                                                                              END                                                                       __________________________________________________________________________

With the system so constituted a 256-state MI Table is provided in thesystem. An example of such a table is as follows:

                  TABLE IV                                                        ______________________________________                                        MESSAGE                                                                       UNIT          D.sub.R  D.sub.S  I                                             ______________________________________                                        223           2509     2509     2509/2509                                      3            2509     2506     2509/2506                                      8            2509     2503     2509/2503                                      26           2509     2500     2509/2500                                      27           2509     2497     2509/2497                                      15           2509     2494     2509/2494                                      43           2509     2491     2509/2491                                     254           2509     2488     2509/2488                                      33           2509     2485     2509/2485                                      53           2509     2482     2509/2482                                     .             .        .        .                                             .             .        .        .                                             .             .        .        .                                             192           2509     1753     2509/1753                                      92           2509     1750     2509/1750                                     250           2509     1747     2509/1747                                      38           2509     1744     2509/1744                                     ______________________________________                                         (256 randomlypaired MI coding)                                           

Wherein each of the 256 message units may be arbitrarily assignedletters and numbers or other digital data. When many-state, such as this256-state MI coding is used the system is especially suitable for datatransmission, confidential data in particular. Using a random order inthe Ml coding, such as that shown in TABLE IV would add a layer ofcomplexity, making it difficult to break as a code.

At the Transmitter 21 each confidential 256-state message is transformedinto an interval-coded wavelet (that means 1 byte of information at atime) according to the secret MI Table, which contains a set of 256message units each of which has been randomly and uniquely assigned to 1of 256 interval-coded durations.

At the Receiver 60 such waves are detected and decoded into the originalconfidential messages 1 byte at a time in accordance with the samesecret 256-state MI coding.

It is not practical to guess at the secret MI coding if such coding isnot provided since the number of permutations in this case involves 256factorial and the secret MI coding can be changed from time to time.Hence, such interval-coded waves, even if intercepted at the pathbetween the Transmitter 21 and the Receiver 60 do not easily reveal themessages being conveyed.

By inserting more reference waves into the signal wave stream theInterval-coded-wave System can tolerate greater frequency drifts/shifts.And in the extreme we may choose to transmit a reference wave next toeach signal wave such as follows: W_(R)(1), W_(S)(1), W_(R)(2), . . . ,W_(R)(N), W_(S)(N), which means that the reference may be changed andup-dated for every single message unit for subsequent intervalevaluation. Such format permits frequency hopping between message units,wherein the intervals may be respectively defined by the waves W_(R)(1)and W_(S)(1), W_(R)(2) and W_(S)(2), . . . , W_(R)(N) and W_(S)(N), etc.

Furthermore, the process and transmitter of the present invention may bepracticed and implemented in another manner to transmit information inthe form of interval-coded tones such as interval-coded musical tones(i.e., tones belonging to a musical scale) which are capable of beingeasily recognized by a human listener who may then identify theinformation encoded therein. Again, this manner of informationtransmission is implemented with the MI table of FIG. 4, the process ofFIG. 5 and the transmitter of FIG. 6. The transmitted toners aremulticycle waveforms. There are shown some suitable waveforms in FIGS.1a-1c. As a concrete example, let us assume that we wish to transmitnumerical values. We could then make up a MI table with suitable musicalintervals such as this:

                  TABLE V                                                         ______________________________________                                                             Reference Signal                                                              Tone      Tone                                           Message              Frequency Frequency                                      Unit     Interval    (Hz)      (Hz)                                           ______________________________________                                        --        0.7500     512       384                                            .         0.8333     512       463                                            0         0.9375     512       480                                            1        1.000       512       512                                            2        1.125       512       576                                            3        1.250       512       640                                            4        1.333       512       682                                            5        1.500       512       768                                            6        1.667       512       854                                            7        1.875       512       960                                            8        2.000       512       1024                                           9        2.250       512       1152                                           etc.                                                                          ______________________________________                                    

FIG. 5 again shows the steps in practicing the process of the presentinvention. From a start at 12 the first step 14 is to establish the MITable such as MI Table V (step 14). The next step 16 is to inputspecific message units M(1) . . . M(N) (for example, the message units"-", "1", "5", and "2", using Table V shown above) at step 16 and selectthe corresponding intervals from the MI Table of 14. The final step 18is to generate and transmit tones W_(R), W_(S)(1), etc. (e.g., the toneseries "512-Hz tone (reference tone), 384-Hz tone (data tone), 512-Hztone (data tone), 768-Hz tone (data tone), and 576-Hz tone (data tone)")in accordance with the input of step 16 and when this is done theoperation is over at step 20. The currently preferred protocol outputsequence is that the reference tone is transmitted first followed by theseries of information tones. The series of tones so generated are usefulas they carry interval-coded information and include a reference withwhich the information may be decoded, whereby information transmissionmay be achieved. The transmitted ted tones may be interpreted by a humanlistener. (Of course, the information carried by these tones may also beautomatically decoded by an above-mentioned Receiver programmed tooperate with multi-cycle waves.) It should be noted that a significantadvantage of implementing the present invention in this manner is thatthe tonal differences of such transmitted musical tones may bedistinguished by a human listener more reliably than other tones bearingnonmusical intervals. A human listener who is skillful in recognizingthe tones of a musical scale may recognize these output tones as tonesbelonging to a musical scale (interval-coded tones) (Even children wouldfind it easy to recognize a simple musical tone series such as, say,"DO-ME-SO" and distinguish it from, say, "DO-ME-LA. ) On hearing thetransmitted tone series the listener may subjectively regard the firsttone in the series as a reference "DO" of a certain musical scale andhence recognize the transmitted tone series as specific tones on thatscale due to their interval relationship (e.g., recognizing them as therelative tone series:

    ______________________________________                                        "DO"    "SO,"     "DO"    "SO"    "RE"  ).                                    ______________________________________                                    

If the MI Table is known and the first tone in the series is also knownto be a reference, the listener may therefore interpret the specificinformation tones in the transmitted tone series as "-", "1", "5", and"2". The system of the present invention provides a tone output methodand transmitter operable as an output means in a specific device orsystem, and may serve as an alternative to visual displays.

Although the specific intervals used in TABLE V belong to a natural(diatonic) scale, corresponding intervals belonging to a slightlydifferent scale such as the equally-tempered scale can also be usedsatisfactorily.

It should be further noted that one of the advantages of the presentsystem is that its principle of operation is non-frequency specific Atransposed frequency set at another pitch can just as well be adopted inTABLE V to generate tones at a higher or lower pitch without departingfrom the specific intervals contained therein. This makes numeroussimilar frequency sets compatible and hence permits greater freedom inthe design of system hardware, and makes transmitters at differentfrequency ranges compatible.

The Transmitter 21 of FIGS. 5 and 6 is employed to carry out the aboveprocess As a specific example of a dedicated version for carrying outthe above process for tones (multi-cycle waves) the transmitter has beenconstructed using a microcomputer 22, a MI Table 26 having its set ofdifferent message units respectively associated to different musicalintervals, i.e., intervals belonging to a musical scale, such as thoseintervals shown in TABLE V above, and a programmable sound generator(e.g., a sound processor chip connected with loudspeaker output) asgenerator 30 to transmit audible tones as output waves at 32 in the formof multi-cycle waves such as those waveforms shown in FIGS. 1a-1c.Specific message units from a source such as a keyboard, a memorylocation or other circuits are sequentially fed to the transmitter at24.

As another concrete example of the process or system of the presentinvention, the transmitter is employed to embody a clock 130 shown inFIG. 15 which measures time and which outputs the component digits ofthe value of time by transmitting interval-coded musical tones 132.These tones "tell" time, and may serve as an alternative to visualdisplays. This clock is embodied by coupling a timer 135 for measuringtime with digital output to and at the front end of the abovetransmitter 21 This clock has been constructed and successfully operatedusing the internal timer of the BBC Microcomputer Model B as timer 135,and the same Microcomputer as microcomputer 22, and the standard soundchip (a SN76489 chip) which is already connected with loudspeaker outputin same Microcomputer as programmable wave generator 30, and TABLE V asMI Table 26 set up in the RAM of same Microcomputer. A suitable programfor the microcomputer 22 of this embodiment is listed below asTransmitter Program III:

    __________________________________________________________________________    Transmitter Program III                                                       __________________________________________________________________________     50  REM INVENTED BY HO KIT-FUN                                                60  REM UNPUBLISHED COPYRIGHT                                                 80  REM MI TABLE                                                              100 PITCHR=101                                                                120 PITCH1=PITCHR                                                             140 PITCH2=PITCHR+8                                                           150 PITCH3=PITCHR+16                                                          160 PITCH4=PITCHR+20                                                          180 PITCH5=PITCHR+28                                                          200 PITCH6=PITCHR+36                                                          220 PITCH7=PITCHR+44                                                          240 PITCH8=PITCHR+48                                                          260 PITCH9=PITCHR+56                                                          280 PITCH10=PITCHR-4                                                          300 PITCH11=PITCHR-12                                                         320 PITCH12=PITCHR-20                                                         500 REM INPUT RESETTIME                                                       510 INPUT"HOUR",HOUR                                                          520 INPUT"MINUTE",MINUTE                                                      530 RESETTIME=(60*HOUR+MINUTE)*6000                                           550 TIME=RESETTIME                                                            600 DIM NOW(6)                                                                610 CHANNEL=1                                                                 615 VOLUME=-12                                                                620 DURATION=10                                                               625 PAUSE%=1000                                                               700 ALARMMODE = 0                                                             800 KEY=INKEY(100)                                                            810 IF KEY=32 THEN GOSUB 1040:                                                    REM PRESS "SPACE BAR" FOR TIME TONES                                      820 IF KEY=65 THEN GOSUB 3500:                                                    REM PRESS "A" TO SET ALARM                                                830 IF ALARMMODE = 1 THEN GOSUB 3800                                          900 GOTO 800                                                                 1030 END                                                                      1040 REM REFERENCE AND MESSAGE TONES                                          1042 SOUND CHANNEL,VOLUME,PITCHR,DURATION                                     1045 FOR PAUSE=1 TO PAUSE%:NEXT                                               1050 NOW=TIME : REM READ INTERNAL TIMER                                       1100 NOW (0)=60                                                               1150 NOW (4)=((NOW DIV 6000)MOD 60)MOD 10                                     1200 NOW(3)=((NOW DIV 6000)MOD 60)DIV 10                                      1250 NOW(1)=((NOW DIV 360000)MOD 24)DIV 10                                    1300 NOW(2) ((NOW DIV 360000)MOD 24)MOD 10                                    1390 N=0                                                                      1400 N=N+1                                                                    1420 PRINT N, NOW(N)                                                          1450 IF N=1 AND NOW(N)=0 THEN GOTO 1400                                       1460 IF N=3 THEN GOTO 3000                                                    1470 IF N=3 AND NOW(N)=0 THEN GOTO 1400                                       1500 ON NOW(N)+1 GOSUB 2000,2010,2020,2030,2040,                                   2050,2060,2070,2080,2090 : REM MI TABLE                                  1600 SOUND CHANNEL,VOLUME,PITCH,DURATION                                      1650 FOR PAUSE=1 TO PAUSE%:NEXT                                               1700 IF N<4 THEN GOTO 1400                                                    1800 RETURN                                                                   1900 REM MI TABLE                                                             2000 PITCH=PITCH10                                                            2005 RETURN                                                                   2010 PITCH=PITCH1                                                             2015 RETURN                                                                   2020 PITCH=PITCH2                                                             2025 RETURN                                                                   2030 PITCH=PITCH3                                                             2035 RETURN                                                                   2040 PITCH=PITCH4                                                             2045 RETURN                                                                   2050 PITCH=PITCH5                                                             2055 RETURN                                                                   2060 PITCH=PITCH6                                                             2065 RETURN                                                                   2070 PITCH=PITCH7                                                             2075 RETURN                                                                   2080 PITCH=PITCH8                                                             2085 RETURN                                                                   2090 PITCH=PITCH9                                                             2095 RETURN                                                                   3000 FOR PAUSE=1 TO PAUSE%:NEXT                                               3010 SOUND CHANNEL,VOLUME,PITCHR,DURATION                                     3015 FOR PAUSE=1 TO PAUSE%:NEXT                                               3020 GOTO 1470                                                                3200 REM ALARMTONES                                                           3205 ALARMMODE=0                                                              3210 REPEAT                                                                   3215 QUIET=0                                                                  3220 GOSUB 1040                                                               3230 FOR PAUSE=1 TO 3*PAUSE% : NEXT                                           3250 QUIET=INKEY(100)                                                         3260 UNTIL QUIET=32 :                                                              REM PRESS "SPACE BAR" TO STOP ALARM                                      3280 RETURN                                                                   3500 REM SET ALARM                                                            3520 INPUT "HOUR", ALARMHOUR                                                  3530 INPUT "MINUTE", ALARMMINUTE                                              3540 ALARMTIME =60 * ALARMHOUR + ALARMMINUTE                                  3550 ALARMMODE = 1                                                            3560 RETURN                                                                   3800 REM TESTTIME                                                             3810 IF INT (TIME/6000) = ALARMTIME THEN GOSUB 3200                           3820 RETURN                                                                   __________________________________________________________________________

In operation the timer 135 keeps the running time. Upon a pre-programmedcondition the microcomputer 22 reads the value of the running time fromtimer 135 and converts it into hour and minute component digits. Thenthe transmitter 21 takes these specific component digits as messageunits and responds by transmitting two interval-coded tone seriesrespectively in a specific protocol output sequence representing thecomponent digits of the value of the running time. This sequence ofoperations is carried out with the above Transmitter Program III. Inthis current embodiment of the clock 130, depressing a key (onmicrocomputer 22) causes the clock to output the current value ofrunning time by transmitting a first tone series representing the hourcomponent decimal digits and a second tone series representing theminute component decimal digits of the time. That is, the clock "tells"time by transmitting firstly the "hour" tones followed by the "minute"tones. For simplicity, it is currently preferred that the mostsignificant component digit be supressed if it is a zero. The exactmanner of time output in this embodiment is further demonstrated withthe following examples: the time, say, 02:35 is transmitted as the toneseries "512-Hz tone (reference), 576-Hz tone (least significant hourdigit)" followed by the tone series "512-Hz tone (reference), 640-Hztone (most significant minute digit), 768-Hz tone (least significantminute digit)", whereas the time, say, 10:05 is transmitted as the toneseries "512-Hz tone (reference), 512-Hz tone (most significant hourdigit), 480-Hz tone (least significant hour digit)" followed by the toneseries "512-Hz tone (reference), 768-Hz tone (least significant minutedigit)".

This embodiment of the clock therefore enables a human listener to"hear" the time.

The transmitter of the present invention is also employed in a monitorsystem to provide a novel alarm feature, wherein an alarm condition hasbeen preset and if the same condition is matched the transmitterautomatically (and repeatedly if so preferred) transmits the tone seriesrepresenting the component digits of the current value of a variablebeing monitored, whereby the transmitted tones may accomplish twopurposes, i.e. providing alarm tones while at the same time conveyingthe updated value of a monitored variable.

Such alarm feature is already successfully embodied in the clockdescribed above, using the same Transmitter Program III above, whereinthe time for alarm may be preset and upon reaching the same time theclock automatically transmits alarm tones in the form of the above toneseries (of clock 130) representing the component digits of the updatedtime value. Such alarm tones are more informative than conventionalalarm tones, as they serve as an alarm while at the same time theyconvey the current component digits of the running time.

Of course, if preferred the above-mentioned clock may be embodied in theform of a digital watch equipped with sound output.

As yet another concrete example to show that the method and system ofthe transmitter may be employed as an output means in specific devicesand instruments, etc , a measuring device 140 is shown in FIG. 16. Thedevice 140 measures a specific analog quantity at input 142 and outputsthe component digits of the measured value by transmittinginterval-coded musical tones 144, and it is realized by coupling ananalog-to-digital converter 146 to and at the front end of transmitter21. In the following specific example described, the device measures aD.C. voltage (which may be the electrical analog of yet another specificquantity) of magnitude between 0 V and 1.80 V. The device has beenconstructed and successfully operated by coupling a PD7002 (A/Dconverter chip) which is already provided in the BBC Microcomputer ModelB to the transmitter 21 embodied with the same Microcomputer. Inoperation the quantity to be measured, in this case a D.C. voltage isinput at an analog input channel (e.g., channel 2) of the PD7002 chip.The microcomputer 22 of the transmitter 21 has been additionallyprogrammed to read the corresponding digital output value from thePD7002 and convert this output value into component decimal digits whichare subsequently taken as the specific message units. Then themicrocomputer 22 of the transmitter 21 operates in the same generalmanner as described in the earlier embodiments; the transmitter 21 takesthe above specific component message units, and subsequently convertsand transmits them as interval-coded tones at output 32. A suitableprogram for the microcomputer 22 to accomplish the operations describedis listed as Transmitter Program IV as follows:

    __________________________________________________________________________    Transmitter Program IV                                                        __________________________________________________________________________     50  REM INVENTED BY HO KIT-FUN                                                60  REM UNPUBLISHED COPYRIGHT                                                 80  REM MI TABLE                                                              100 PITCHR=101                                                                120 PITCH1=PITCHR                                                             140 PITCH2=PITCHR+8                                                           150 PITCH3=PITCHR+16                                                          160 PITCH4=PITCHR+20                                                          180 PITCH5=PITCHR+28                                                          200 PITCH6=PITCHR+36                                                          220 PITCH7=PITCHR+44                                                          240 PITCH8=PITCHR+48                                                          260 PITCH9=PITCHR+56                                                          280 PITCH10=PITCHR-4                                                          300 PITCH11=PITCHR-12                                                         320 PITCH12=PITCHR-20                                                         610 CHANNEL=1                                                                 615 VOLUME=-12                                                                620 DURATION=10                                                               625 PAUSE%=1000                                                               690 KEY=GET                                                                   700 REM 0 <= VOLTAGE <= 1.8                                                   705 VOLTAGE = 1.8*ADVAL(1)/65520 : REM MEASURE VOLTAGE                        710 V0 = INT VOLTAGE                                                          720 V1 = INT (VOLTAGE*10)MOD 10                                               730 V2 = INT (VOLTAGE*100)MOD 10                                             1040 REM REFERENCE AND MESSAGE TONES                                          1042 SOUND CHANNEL,VOLUME,PITCHR,DURATION                                     1045 FOR PAUSE=1 TO PAUSE%:NEXT                                               1490 PRINT V0:                                                                1495 REM MI TABLE                                                             1500 ON V0+1 GOSUB 2000,2010,2020,2030,2040,2050,                                  2060,2070,2080,2090                                                      1510 GOSUB 1600                                                               1518 PRINT ".";                                                               1520 PITCH=PITCH11:GOSUB 1600:REM DECIMAL POINT                               1528 PRINT V1;                                                                1530 On V1+1 GOSUB 2000,2010,2020,2030,2040,2050,                                  2060,2070,2080,2090                                                      1540 GOSUB 1600                                                               1548 PRINT V2                                                                 1550 On V2+1 GOSUB 2000,2010,2020,2030,2040,2050,                                  2060,2070,2080,2090                                                      1560 GOSUB 1600                                                               1590 GOTO 690                                                                 1600 SOUND CHANNEL,VOLUME,PITCH,DURATION                                      1650 FOR PAUSE=1 TO PAUSE%:NEXT                                               1800 RETURN                                                                   1900 REM MI TABLE                                                             2000 PITCH=PITCH10                                                            2005 RETURN                                                                   2010 PITCH=PITCH1                                                             2015 RETURN                                                                   2020 PITCH=PITCH2                                                             2025 RETURN                                                                   2030 PITCH=PITCH3                                                             2035 RETURN                                                                   2040 PITCH=PITCH4                                                             2045 RETURN                                                                   2050 PITCH=PITCH5                                                             2055 RETURN                                                                   2060 PITCH=PITCH6                                                             2065 RETURN                                                                   2070 PITCH=PITCH7                                                             2075 RETURN                                                                   2080 PITCH=PITCH8                                                             2085 RETURN                                                                   2090 PITCH=PITCH9                                                             2095 RETURN                                                                   2098 END                                                                      __________________________________________________________________________

In this specific example, the device 140 functions as a digitalvoltmeter. When a voltage of, say, 1.50 V is measured the deviceconverts the measured value into a series of specific message units, inthis case into "1", ".", "5", "0" and, in the general manner describedearlier and in accordance with TABLE V, transmits a correspondinginterval-coded tone series, in this case the following tone series:"512-Hz tone (reference), 512-Hz tone (data), 463-Hz tone (data), 768-Hz(data), 480-Hz (data)". It is understood that other A/D converters,voltage dividers, etc. may be employed in the device for measuring othervoltage ranges.

From the several embodiments described, it is clear that the tone outputmethod and the transmitter of the present invention may be practiced andemployed in various systems and devices, such as digital multimeter,thermometer, pressure meter, etc., and may serve as an alternativeoutput means to visual displays. And in various such embodiments theoutput protocol can be changed if preferred, such as by using the lasttone in the transmitted tone series to code the exponent of the value ofthe quantity being expressed. For example, still using TABLE V, a valueof say "350000" is expressed and transmitted as the following toneseries "512-Hz tone (reference), 640-Hz tone (data), 768-Hz tone (data),682-Hz tone (data)" to convey "3" and "5" followed by four zeros.

From the foregoing description, it will be apparent that the system ofthe prevent invention provides a method and system for communicationwhich has advantages over the prior art.

While several embodiments of the system of the invention have been shownand described, changes and modifications may be made to the systemwithout departing from the teachings of the invention and, therefore,the invention is only to be limited as necessitated by the accompanyingclaims.

I claim:
 1. A process of information transmission, wherein theinformation consists of a series of specific message units out of a setof possible message units, comprising the steps of:(a) defining aperiodic property ratio relationship with reference to a referenceperiodic property for each of the members of the set of possible messageunits; (b) converting and transmitting the information series ofspecific message units into a set of signals including a referencesignal and a series of information signals each having a a periodicproperty related to the reference signal's periodic property by theratio relationship defined for that specific message unit in thepreceding step; and (c) receiving said signals and by determining theperiodic property ratio relationship between the reference andinformation signals, converting them to the defined series of specificmessage units, whereby information transmission may be achieved.
 2. Theprocess of claim 1, wherein information is transmitted and receivedbetween two stations each of which employs the process of claim 1 usingthe same definitions but wherein each station transmits using adifferent reference periodic property.
 3. The process of claim 1 whereinthe reference signal is transmitted first followed by the series ofinformation signals.
 4. The process of claim 1 wherein the series ofinformation signals are transmitted by sequentially transmitting asingle wavelet of half a cycle.
 5. A signal transmitter for transmittinga message comprising a series of specific message units, saidtransmitter comprising:(a) means for generating signals; (b) means forreceiving the series of specific message units; and (c) control meanscoupled to said generating means and to said receiving means forsequentially generating and transmitting a reference signal having areference periodic property and, for each of said received messageunits, an information signal having a periodic property representativeof a specific ratio relationship to said reference periodic property,said specific ratio relationship being invariant for a given messageunit, whereby the transmitted signals are tolerant of shifts such asDoppler shift.
 6. The transmitter of claim 5 wherein the referencefrequency signal is transmitted first followed by the series ofinformation signals.
 7. The transmitter of claim 5 wherein the signalsare respectively single half-cycle signals.
 8. The transmitter of claim5 wherein the series of information signals are transmitted bysequentially transmitting a single half-cycle.
 9. A signal receiver forreceiving and decoding signals comprising:(a) an input unit forreceiving signals, including a reference signal and an informationsignal, each having a periodic property, and for determining theperiodic property, and for determining the periodic property of receivedinformation and reference signals; (b) means defining each member of aset of possible message units, such as an alphabet, as differentspecific ratio relationships between an information periodic property ofthe information signal and a reference periodic property of thereference signal; (c) means inter-coupled with said defining means andsaid input unit for producing a series of message units in response tothe received signals in accordance of said defined ratio relationships.10. The receiver of claim 9 including means for receiving said referencesignal first followed by said information signal.
 11. The receiver ofclaim 9 wherein said defining means includes means for defining amessage unit for a continuous range of intervals between certainspecific values.
 12. The receiver of claim 9 including means forsequentially receiving a variety of reference signals havingdistinguishable periodic properties.
 13. A process for transmittinginformation comprising a series of specific message units, said processcomprising the steps of:(a) inputting said series of specific messageunits; (b) generating in response to each of said input message units amessage tone at a frequency representative of a specific tone frequencyratio to a reference tone frequency, said specific frequency ratio beinginvariant for a given message unit; and (c) relating and transmittingsaid generated message tone in sequential order in a tone seriesincluding said reference tone, whereby information transmission may beachieved.
 14. The process of claim 13 wherein the reference tone istransmitted first followed by the series of message tones.
 15. Theprocess of claim 13 wherein the specific tone frequency ratios includeratios which result in the message tone being cognizable by a listeneras a note of a musical scale, such as a diatonic scale or anequally-tempered scale.
 16. The process of claim 13 wherein the specifictone frequency ratios include 1.000, 1.250, 1.333, 1.500, 1.667, 1.875,and 2.000.
 17. A tone transmitter for transmitting informationcomprising a series of specific message units, said transmittercomprising:(a) means for generating tones; (b) means for receiving theseries of specific message units; (c) control means coupled to saidgenerating means and to said receiving means for sequentially generatingand transmitting a reference frequency tone and, for each of saidreceived message units, a message tone at a specific frequency ratio tothe frequency of said reference frequency tone, said specific frequencyratio being invariant for a given message unit.
 18. The tone transmitterof claim 17 including means for transmitting the reference frequencytone first followed by the series of message tones.
 19. The tonetransmitter of claim 17 wherein the specific tone frequency ratiosinclude ratios which result in the transmitted message tone beingcognizable by a listener as a note of a musical scale, such as adiatonic scale or an equally-tempered scale.
 20. The tone transmitter ofclaim 17 including means for changing the reference tone frequencyfollowing the transmission of a message tone.
 21. The tone output devicein a measuring system for measuring a specific quantity, comprising:(a)means for generating tones; (b) means for receiving the component digitsof a measured value of a specific quantity; and (c) control meanscoupled to said generating means and to said receiving means forsequentially generating and transmitting a reference frequency tone and,a said received component digit, a message tone at a specific frequencyratio to the frequency of said reference frequency tone, said specificfrequency ratio being invariant for a given component digit.
 22. Thetone output device of claim 21 further including table means forassigning specific frequency ratios for the message tones.
 23. The toneoutput device of claim 21 including means for transmitting the referencefrequency tone first followed by a series of message tones.
 24. The toneoutput device of claim 21 wherein the specific frequency ratios includeratios which result in the specific message tone being cognizable by alistener as a note of a musical scale, such as a diatonic scale or anequally-tempered scale.
 25. The tone output device of claim 21 includingmeans for assigning to a set of digits, message tones, respectively,including those tones of frequencies representative of specificfrequency ratios 1.000, 1.125, 1.250., 1.333, 1.500, 1.667, 1.875 and2.000.
 26. A timing device with tone output means, comprising:(a) meansfor measuring time represented by component digits; (b) means coupled tosaid measuring means for converting each of said component digits into amessage tone at a specific frequency ratio to a reference frequencytone, said specific frequency ratio being variant for a component digit;(c) means coupled to said converting means for relating and transmittingsaid message tone and said reference frequency tone in sequential orderin a tone series, whereby the time value may be transmitted.
 27. Thedevice of claim 26 including means for transmitting the referencefrequency tone first followed by a series of message tones.
 28. Thedevice of claim 26 wherein the specific frequency ratios include severalspecific frequency ratios which result in a specific message tone whichis cognizable by a listener as a note of a musical scale, such as adiatonic scale or an equally-tempered scale.
 29. The device of claim 26wherein the specific frequency ratios include tone frequency ratios1.000, 1.125, 1.250, 1.333, 1.500, 1.667, 1.875, and 2.000.
 30. Thedevice of claim 26 including means for detecting a predeterminedcondition such as a depressed key or passing of the time for alarm, andfor causing the clock automatically to transmit an alarm tone seriesincluding the reference frequency tone and the message tones for thespecific component digits of the time.
 31. An analog measuring devicefor representing a measured analog quantity, comprising:(a) first meansfor converting an analog quantity component to representative componentdigits; (b) second means coupled to said first converting means forconverting each of said component digits into a message tone at aspecific tone frequency ratio to a reference frequency tone, saidspecific tone frequency being invariant for a component digit; and (c)means coupled to said second converting means for relating andtransmitting said message tones and said reference frequency tone insequential order in a tone series, whereby the measured analog quantitymay be transmitted.
 32. The measuring device of claim 31 including meansfor transmitting the reference frequency tone first followed by theseries of message tones.
 33. The measuring device of claim 31 whereinthe specific tone frequency ratios include ratios which result in amessage tone being cognizable by a listener as a note of a musicalscale, such as a diatonic scale or an equally-tempered scale.
 34. Themeasuring device of claim 31 wherein the specific tone frequency ratiosinclude 1.000, 1.125, 1.250, 1.333, 1.500, 1.667, 1.875, and 2.000,operable with tolerance.
 35. A process for recording informationconsisting of a series of message units selected from a set of definedmessage units, said recording process comprising the steps of:(a)defining the message units comprising the set of defined message units;(b) assigning a message unit ratio to each defined message unit; (c)providing a periodic reference signal having a reference periodicproperty; (d) converting each message unit of the information to berecorded into a set of signals including said reference signal, eachmessage unit being a member of the set of defined message units andrelated to said reference signal by a specific message unit ratio; (e)providing an information signal having an information periodic property,said information periodic property being varied for each message unit toconform to the message unit ratio for each message unit; (f) recordingsaid periodic reference signal and said information signal; (g) uponplayback receiving said periodic reference signal and said informationsignal; (h) determining a received message unit ratio between saidreference periodic property and said information periodic property ofthe received signals; and (i) deconverting said received message unitratio to a message unit in accordance with the assigned message unitratio, thereby to retrieve the information.
 36. The process of claim 35wherein said periodic reference signal is recorded first followed bysaid information signal.
 37. The process of claim 35 wherein the periodof the periodic reference signal is changed after the information signalhas been recorded with the varied information periodic property for amessage unit.
 38. The process of claim 35 wherein said informationperiodic property is recorded for one half of the duty cycle of theinformation signal established by each message unit.